1. Field of the Invention
This disclosure relates to a rechargeable lithium battery.
2. Description of the Related Art
Batteries transform chemical energy generated from an electrochemical redox reaction in the battery into electrical energy. Such batteries are divided into a primary battery, which should be disposed after the energy inside the battery is consumed, and a rechargeable battery, which can be recharged.
The rechargeable battery can be charged/discharged several times based on the reversible transformation between chemical energy and electrical energy.
Recent developments in the high-tech electronics industry allows electronic devices to become small and light in weight, which leads to an increase in portable electronic devices. As a power source for such portable electronic devices, the demands for batteries with high energy density are increasing and research on lithium rechargeable batteries is under progress.
The rechargeable lithium battery is fabricated by injecting electrolyte into a battery cell, which includes a positive electrode including a positive active material capable of intercalating/deintercalating lithium ions and a negative electrode including a negative active material capable of intercalating/deintercalating lithium ions. The negative active material includes compounds alloying with lithium and oxides thereof.
The compound alloying with lithium may include lithium titanate (LTO). The lithium titanate has relatively high oxidation reduction potential and thus, may not only have almost no electrolyte decomposition but also stable crystal structure, resulting in excellent cycle characteristic.
However, when the lithium titanate is used as a negative active material, it may suffer volume-expansion at a high temperature and thus, increase the thickness. This thickness increase may deteriorate output and capacity as well as bring about external transformation of the battery.